Flexible PCBs are light and thin circuit boards that use polyimide materials and rolled copper foils. Get to know flexible PCB structures, types, uses, and pros now.
A flexible PCB is a special printed circuit board that uses the thin and bendable polyimide (PI) substrate to replace the rigid FR4/metal/PTFE/ceramic substrate and PI coverlay to replace the solder mask. It uses the non-conductive PI materials to insulate and protect the conductive copper traces that connect different flexible PCB layers by plated through-holes or buried vias.
Compared with normal rigid PCB boards, flexible Flexible PCBs are extensively used in electronics devices and systems in telecommunications, automotive, industrial, medical, defense, aerospace, consumer electronics. Why are flex PCBs so favored? Let's see the details of flexible PCBs and find the answer!
A flexible PCB is also known as a flexible circuit board, flex PCB, FPC. Copper circuit traces are etched on the non-conductive flexible polyimide materials, and different circuit layers are interconnected by plated through holes (PTH) or buried vias. On the two sides of a flexible PCB, electronic components can be surface-mounted on the PCB pads. For better mechanical support, sometimes, PCB stiffeners can add to the ends of flexible PCBs for connection with the system/device/other parts.
Like traditional PCBs, flexible PCBs are custom designed and manufactured, and they can be single-sided, double-sided, single-layer, dual-layer, or multi-layer. One circuit layer counts one PCB layer. But flexible PCBs are so different from traditional rigid PCBs, and everyone can identify them immediately - flexible PCBs are thin, light, and usually, yellow.
And the thickness range of flexible PCBs falls within 0.05mm to 0.6mm. This is also the finished flex PCB thickness range from PCBONLINE.
Flexible PCBs are usually double-sided. To better understand flexible PCBs, you need to know the basic structure of flexible PCBs.
The above image shows the structure of a 4-layer flexible PCB with a PTH hole. A flexible PCB consists of:
A PI substrate is laminated with two copper layers on its two sides. A two-layer flexible PCB consists of a PI substrate, two rolled copper layers, two PI layers (coverlay). Multilayer flexible PCBs are manufactured by laminating alternating layers of copper and PI on the flexible PCB core.
According to circuit layers differences, there are single-layer FPC, two-layer FPC, multilayer FPC.
According to component mounting side differences, there are single-sided FPC, double-sided FPC.
According to FPC laminate differences, there are yellow polyimide FPC, clear flexible PCBs, flexible aluminum PCBs.
According to FPC vias differences, there are HDI flexible PCBs, normal flexible PCBs.
Here I give a brief introduction to some special flexible PCB types.
Clear flexible PCBs use transparent polyimide laminate. From PCBONLINE, a leading FPC manufacturer, the normal clear flexible PCBs have a thickness range of 0.06mm to 0.1mm, a maximum PCB layer of 8. The surface finish of clear flexible PCBs is usually immersion silver or immersion tin.
Clear flexible PCBs are about 5 to 10 times more expensive than normal yellow polyimide PCBs. The detailed price should be quoted according to your Gerber files. You can get free design/engineering help or clear flexible PCB quotation by sending your Gerber to our email firstname.lastname@example.org.
HDI flexible PCBs are high-density-interconnect flexible PCBs that have buried/blind microvias. According to IPC standards, HDI flexible PCBs have the FPC via aperture of 0.25mm and below, trace width/space of 0.1mm and below.
HDI flexible PCBs are multilayer, with a PCB layer of 4, 6, 8, or 10. You can have HDI flexible PCBs manufactured from PCBONLINE.
PCBONLINE is a one-stop flexible PCB manufacturer providing flexible PCB manufacturing, assembly, design, component sourcing, end-product assembly. PCBONLINE, founded in 1999, has two large advanced PCB manufacturing bases in Jiangsu and Jiangxi, one flexible PCB assembly factory in Shenzhen.
From PCBONLINE, you can order 1 to 10-layers of yellow polyimide flexible PCBs, 1 to 8 layers clear flexible PCBs, single/double-sided flexible PCBs, HDI flexible PCBs, flexible aluminum PCBs, aluminum LED PCBs.
Here are the reasons to let PCBONLINE manufacture your flexible PCBs:
Please feel free to contact PCBONLINE by email at email@example.com to get a flexible PCB quotation or free engineering consultancy.
Flexible PCBs can be used in almost all electrical and electronics industries. However, flexible PCBs are more expensive than normal rigid PCBs, and they have been extensively used in these industries:
Flexible circuit boards are used in automotive systems/parts including anti-lock braking systems, airbag controllers, dash systems, instrumental panels, etc. Flex PCBs fit into the small parts and provide flexibility for engineers. Automotive components need to withstand heat and cold and experience vibration during use. There is no need to worry about flexible PCBs in such circumstances.
Flexible PCBs are used in different parts of the aviation industry, such as in holographic waveguide helmet-mounted displays providing high-resolution 3D images. In satellites, flexible PCBs are used to replace connectors that may cause interconnect errors, and they can fold and bend thousands of times, carry components, and directly connect different parts.
Computer operations rely on flexible PCBs as computers have a small space and flex PCBs pass signals. Desktops usually apply 4 and 6 layers FPC boards, and laptops with a smaller space require 8-layers FPC boards.
Smartphones are tiny, light-weighted, portable, and multifunctional. Inside the small smartphones, there are plenty of flexible PCBs used to carry and connect various components. Flex PCBs fit tiny spaces and keep our smartphones safe, and they are resistant to heat and the environment.
Flexible PCBs are extensively used in medical appliances such as swallowable pill cameras, gastroscopy, glass hearing devices, etc. Flexible PCBs are small, thin, foldable, and durable, and these metrics make them necessary for medical devices that have a small space and require precision. Below is a double-sided flexible PCB for gastroscopy.
Besides, flexible PCBs are also used in wearable devices, digital cameras, etc. Flexible PCBs are extensively used in these middle and high-end devices because of the below advantages.
This article gives a comprehensive introduction to flexible circuit boards. I hope you can have a deep insight into flexible PCBs by reading this article. If you want to know more specifications of flexible PCB manufacturing and assembly, or you want to design/manufacture/assemble flexible PCBs, please feel free to contact the reliable one-stop FPC manufacturer PCBONLINE.